1. Field of the Invention
The present invention relates to dive meters for SCUBA (self-contained underwater breathing apparatus) divers, and more particularly, to an ascent rate meter for a portable data sensor, processor, and display mounted in a waterproof case for continuously determining the ascent rate of a SCUBA diver during an underwater dive.
2. Description of the Prior Art
There are many types of dive meters for SCUBA divers which have been designed for the purpose of aiding a SCUBA diver during a decompression ascent to avoid the bends. They are data sensing and processing devices which comprise sensors, computers, and display gauges which sense depth, pressure in the diver's air tank, dive time, and contain the U.S. Navy dive tables or a modification thereof in the computer memory to provide an integrated information readout on the displays of the meters.
In addition, there are more sophisticated devices which aid an underwater sport diver to avoid the necessity of a decompression ascent. Reference is made to U.S. Pat. No. 4,882,678 issued Nov. 21, 1989, to some of the co-inventors of the present invention entitled, "Data Sensing and Processing Device for SCUBA Divers," which describes the latter type meter.
It has been determined that there is an important parameter of information for SCUBA divers which has not been incorporated in the meters of the prior art before the advent of the present invention. That is an ascent rate meter.
Runaway ascents for SCUBA divers can lead to decompression sickness and air embolism, and thus the control of ascent rates is generally recognized as an important safety issue. However, in order for a diver to control his ascent rate, it is necessary for the diver to have an accurate means of knowing just what that ascent rate actually is. The purpose of the present invention is to establish a means for accurately calculating a diver's ascent rate in order that this information can be added to the displays of dive meters presently used by SCUBA divers for sport and commercial diving.